Batting Average: Divide the number of hits by at-bats.
Slugging Percentage: Divide the total bases of all hits by the total official times at bat (Single = 1 base, double = 2 bases, triple = 3 bases, home run = 4 bases).
Earned Run Average: Multiply the total earned runs by 9 and divide the result by the total number of innings pitched
Winning Pitcher: The starting pitcher will be credited with the win only if he has pitched at least five complete innings and his team not only is in the lead when he is replaced, but remains in the lead the remainder of the game. EXCEPTION: The "must pitch five complete innings" rule in respect to the starting pitcher shall be in effect for all games of six or more innings. In a five-inning game, his team not only is in the lead when he is replaced, but remains in the lead the remainder of the game. When the starting pitcher does not meet the preceding criteria and more than one relief pitched is used, the victory shall be awarded on the following basis:
(1) When, during the tenure of the starting pitcher, the winning team assumes the lead and maintains it to the finish of the game, credit the victory to the relief pitcher judged by the scorer to have been the most effective.
(2) Whenever the score is tied, the game becomes a new contest insofar as the winning and losing pitcher is concerned.
(3) Once the opposing team assumes the lead, all pitchers who have pitched up to that point are excluded from being credited with the victory except the current pitcher.
(4) The winning relief pitcher shall be the one who is the pitcher of record when his team assumes the lead and maintains it to the finish of the game. EXCEPTION: Do not credit a victory to a relief pitcher who is ineffective in a brief appearance, when a succeeding relief pitcher pitches effectively in helping his team maintain the lead. In such cases credit the succeeding relief pitcher with the victory.
Save Rule: Rule 10.20 tells the official scorer to credit a pitcher with a save when he meets all three of the following conditions: (1) He is the finishing pitcher in a game won by his club; and (2) He is not the winning pitcher; and (3) He qualifies under the following conditions: (a) He enters the game with a lead of no more than three runs and pitches for at least one inning; or (b) He enters the game with the potential tying run either on base, at bat or on deck (that is, the potential tying run is either already on base or is one of the first two batsmen he faces); or (c) He pitches effectively for at least three innings.
Blown Save Definition: When a relief pitcher
enters a game in a save situation and departs or the game ends with the
save situation no longer in effect because he has given up the lead, he
is charged with a "blown save." If the save opportunity still exists when
he leaves the game, he is not charged with a save opportunity. If the pitcher
has not given up the lead when he leaves the game, though the save opportunity
may no longer exist, he is not charged with a save opportunity.